A significant value (FCT = 0.001, P = 0.04, 0.10% of the
variation) was calculated only when the samples were
grouped into western Atlantic and Gulf of Mexico. The
analysis did not support the existence of separate populations
within the Gulf, nor within the Atlantic, and the negligible
and insignificant amount of variation among years
within Charleston Harbor, SC (0.06% of the variation) was
equivalent to that found among the other Atlantic samples
(−0.08%).